The present invention pertains to a plate-shaped shearing knife for shearing off allotments of liquid glass, the knife having a roughly V-shaped or circular-shaped cutting region and a wedge-shaped cross section with respect to its thickness.
Shearing knives of this kind are used in pairs in fully-automated systems, and use opposing movements to shear off glass allotments from a stream of liquid glass from a glass reservoir, these allotments can then be processed into glass bottles, container glass, video screens, and similar products.
In particular, when shearing off small allotments of glass, as occurs in the manufacture of glass bottles, container glass, or incandescent light bulbs, the shearing process takes place at a very high frequency, i.e., about 100 shearing steps per minute or more.
Because of this high frequency, the shearing knives are in direct contact with the glass melt over a relatively long period of time, and this glass melt has a temperature of between about 1100° C. and 1300° C. depending on the type of glass and the glass article to be manufactured. Thus, the knives are heated to temperatures of up to about 400° C. by the glass melt in spite of cooling of the knife by cooling emulsions. As a result, the wear of the shearing knife is accelerated.